The Blood Code
by sinnamonroll21
Summary: A midnight murder. A message written in blood and codes. These are the sole link to Pitch Black, the most dangerous criminal in the world, and the arch-enemy of Jack Frost, a special agent of FBI. In this mission, Jack has to work Elsa Sorensen, a tech genius. Together they gradually unravels the mystery of Pitch Black. However, not everything goes as expected. Modern AU.
1. Prologue

A/N: Hi everyone! My name is Piper (not my real name), and although I've opened this account for quite a while, I'm still new to FFN 'cause I hardly ever visit the site. I'm a huge fan of Sherlock Holmes, both the original version and the BBC _Sherlock_ version, Dan Brown and Lee Child. Basically, I love thrillers, detective stories and spy novels and films. Of course, I also love Disney (who doesn't?) and Dreamworks (I think most people do, too) and the ship Jelsa (um, isn't this the main reason why we're all here?).

Anyway, enough of me. Let's talk about this story. First of all, it's my very first fanfic, so take it easy on me, will ya? Be nice to the newbie. Also, I'm an Asian and know practically nothing about how things operate in America so forgive me and please point out to me if anything in the story is inaccurate. English isn't my first language, but I'm confident enough in my English skills that you will only see a couple of grammatical or spelling mistakes here and there.

Another thing is that this story will include pretty many elements inspired by or based on Sherlock Holmes, the Da Vinci Code (by Dan brown) and A Wanted Man (by Lee Child). I mean, duh, those are my favourites (ROTG and Frozen not included, of course). Therefore, Jack Frost in this story will be a combination of Sherlock, Robert Langdon, Jack Reacher and (of course) himself. Will there be Jelsa? Um, hello? If not, then what's the freakin' point here?

One warning! If you're wondering whether this story is planned out already, then my answer, sadly, will have to be no. I have a plan in mind, but it's rather vague, and I'm mostly improvising here. So there are good news and bad news. Good news is you're free to contribute your ideas and whatever. Bad news is this may not make it to the end. But, I think with your help and encouragement, it might not turn out to be a problem at all. So remember to leave your comments as well as your ideas, provided that you have one, or some, in mind. If not, 'tis okay. You can just sit back and enjoy the show.

Anyway, I've just decided that I've rambled enough. Better shut my mouth now.

It's show time.

* * *

Prologue

Jack Frost was sleeping soundly when suddenly the world around him trembled violently, like an earthquake shaking through his whole being. His eyes snapped open and was immediately blinded by a dazzling light shining directly at him. He squinted and tried to move, but his arms felt numb, his legs leaden and his torso seemed to have been frozen to the bed beneath him. Groaning, he gathered all his strength and rolled to one side, reached out and fumbled for something. Finally, he found it and grabbed the object. It was his phone and it was buzzing warmly in his palm. He tried to read the caller ID but everything seemed to be enveloped in a veil of mist. Jack blinked. Once, twice, and after a few more times his vision was clear again, and his brain was once more functioning properly.

'Who's that, mate?' asked his comrade and roommate, Edmund Aster, nicknamed Bunny, his voice still laced with grogginess.

'It's North,' replied Jack, now fully awake. Nicholas St. North was their boss and he was calling him, which was very strange since normally North would tell one of his men, usually Phil, to make a call. He glanced at the time. It read 2.53 am, which was even stranger. If North had to personally call him at this ungodly hour, then it could only mean one thing.

Pressing 'Answer', he said: 'When?'

'An hour ago,' said North through the phone. 'No witnesses. Nightmare's work again.'

Nightmare. Jack scowled at the name. Pitch Black the Nightmare was the most dangerous criminal on earth. And he was Jack's arch-enemy.

But there was something strange about this case. Otherwise North wouldn't have called.

'Was there anything peculiar?'

'Yes. There was a message.'

'From the victim?'

'No. From the killer.'

'Send me the location.' Ending the call, he hopped out of bed and looked at Bunny, who was now just as awake as him and still ignorant of what was the hell was going on. 'Get your cotton-tailed ass out of your burrow, you Easter kangaroo. We've got a new case.'

* * *

About an hour later, Jack and Bunny were present at the crime scene. The local forces were already there, and the FBI had been sniffing around for a while. _Figured_ , Jack thought, letting his eyes roam his surroundings.

'Jack! Bunny! Over here!' a feminine voice called out to them.

A woman was waving at them. She was just a little above the average height and shy of thirty-seven. She was slender, with full hips, short black hair that barely touched her shoulders, tan skin, a heart-shaped face and dark eyes shaped like almond. She was pretty, the Western kind of pretty, but she also had the Eastern charms.

'Tooth!' Jack and Bunny both gave her a quick hug. Tooth, whose real name was Thiana Tran, was a woman of South-East Asian origins, and whom the two of them practically grew up with. The name Tooth came from Jack. When she first came to their neighbourhood, Thiana was this shy, half American and half Asian girl with a tiger's fang hanging on the string around her neck whose name was so hard to pronounce for Jack, who was barely a toddler then. So he used to most distinguishing mark on her to identify her - the fang, but then there was only one word that he knew to describe it, which was 'tooth', and since then Thiana Tran became Tooth.

'Where's North?' asked Jack. The three of them were close friends, true enough, but there was hardly any time for pleasantries at this moment. They needed to go straight to business.

Tooth led them to the abandoned warehouse. It was just like any abandoned warehouse, nothing particular, nothing out of ordinary. North was inside, along with several other FBI agents.

'Ah! Jack, Bunny! Finally you've come!' exclaimed North. He was a giant of a man, with a massive torso and tree trunks for arms. He was past fifty, nearly sixty. His hair was all white, but somehow his brows still managed to retain its black colour and his face still looked quite youthful for his age. Unlike Tooth, he wore no jacket. The sleeves of his blue shirt was rolled up, revealing his forearms, which were covered with black tattoos. Nicholas St. North was an intimidating man, for someone who didn't know him or someone who had just pissed him off. Well, he was pissed off right now, at somneone who was not there, but he still intimidated everyone else nonetheless.

Except those who really knew him.

'So where's the dead man?' asked Bunny.

'Come,' said North with a wave of his hand.

It was dark inside, and tonight the moon was hidden somewhere, beyond the clouds. Even with the flashlights, it was hard to see. Not that Jack minded. He had been in this job for nigh on ten years. He was used to it.

'So who found him?' Jack asked.

'Some drunken man who wandered further than he should and got lost. He thought he could find a place to lay down for a while here. What he didn't know, however, is that someone else already beat him to it. Ah! There he is! Go and look all you want, Jackie-boy. He's all yours.'

Jack made his way towards the corpse. It was male, probably in his late forties. He was lying on his back, with his head rolled to one side, his eyes still wide open and his mouth slightly parted, his arms and legs spreading on either of his sides. There were small bruises and cuts here and there on his face and arms, coupled with some pieces of broken wood and fallen stuff around; it was evident that there had been some fighting between the victim and the killer. Jack inspected the body again. The victim was stabbed, not shot - which was very odd, for all victims of Nightmare were killed by guns. The knife had gone from under the ribs. The man did not die instantly. He must have had at least a couple of minutes before he died of blood loss.

 _Someone had moved him_ , Jack concluded as his eyes glided over the blood smeared on the floor, leaving a crimson trail near the dead guy. He glanced at the body again. His legs were closed, and his arms were spread, forming a perfect V.

 _Impossible_ , Jack thought. _This can't be Nightmare's work. He always makes sure that the victim dies instantly._

'He's been dead for about three hours,' Jack concluded. 'Stabbed by some sort of curved knife. Eight to nine inches, I'd presume. There had been a fight between the two of them prior to this, suppose there were only two people, the victim and the killer. Are you sure this is Nightmare's work?'

'Certain.'

'Have our tech guys managed to indentify this man yet?'

'No. They're still looking.'

'So what's the message?'

North pointed his flashlight to the right. 'There. In the corner.'

Jack and Bunny followed North's instructions and found a message written on the wall.

A message written by blood.

Jack had expected to see some sort of threat, a warning, a hint about another upcoming death, some kind of blackmail, but this was by far the weirdest message ever. Especially from such a notorious criminal.

There was a sequence of numbers arranged in no particular order, written backwards. The numbers were all slanted, but some to the left and some to the right, again in no particular order. They looked like they were going to crash into each other and fall at some point if no one were to steady them.

 _ **1**_ **-2-** _ **12**_ **-** _ **12**_ **8-6-** _ **8**_ **-12-** _ **12**_ **-** _ **4**_ **12-7-11-8**

 _ **12**_ **-** _ **11**_ **-12-** _ **9**_ **-13-** _ **7**_ **-12** _ **6**_ **-9-12** _ **13**_ **-** _ **5**_

 **12-2-6-9** _ **1**_ **-11-** _ **12**_

But there was something that caught his eyes most. A dagger was plunged deep into the wall, with ornately decorated silver hilt and a sparkling ruby at the pommel. Two words were carved on the wall next to it. Two words he despised most. Two words that confirmed his greatest fear.

 **PITCH BLACK**

* * *

'It makes no sense,' Jack grumbled as he continued pacing back and forth. The picture of the message was still in his hand and his eyes refused to leave it. Sixteen minutes and forty-eight seconds. For sixteen minutes and forty-eight seconds he'd been staring at the picture, wracking his brain trying to figure out what the symbol meant, what those numbers meant, and why Pitch Black _himself_ would leave a message with his own weapon, which he apparently had just used to kill his victim, and signed his own _goddamn_ name.

'Well, that's why we have to solve it, mate,' said Bunny as he casually leaned against their car and inspected his nails.

'Why did he use the victim's blood to write that message? If he wanted to tell us something, why wouldn't he just... write that down already? Why use codes and make us guess the meaning?' inquired North, scratching his bearded chin.

Suddenly, Jack stopped pacing. He drew a sharp gasp and his eyes was mumbling something inaudible, something about 'blood'.

'Come again?' Bunny asked, pushing himself upright.

'It wasn't the victim's blood,' Jack said again, now louder. Or perhaps too loud because now several others were looking at him.

'What?'

'Yes! It wasn't the victim's blood. Test the DNA if you want proof. Look at these pictures,' he slammed three photos on the hood of the car. 'See? There are clearly signs of struggles between them. They must have fought. I don't think the murder was intentional.'

'But... how?' asked Tooth, evidently stunned.

'Yeah. How? Pitch Black is an assassin. He _kills_ people. That's what he does all the time. I don't think he ever _intends_ to _not_ kill anyone,' countered Bunny.

'Maybe this time is different,' Jack stubbornly held his ground. 'Look. My guess is that these two arranged to meet. This guy is a gang member, I'm sure of it, but you can check him later and see how I came to that conclusion. It was supposed to be a professional, non-violence meeting, but I guess something went out of hand and the other guy sparked up the fight. Pitch was injured, and was forced to kill the guy to defend himself.'

'Why would you think like that?' wondered North.

'Because of his handwriting,' Jack slammed another picture on the desk, one of Pitch Black's message. 'We all are professionals here. It's obvious that he was shaking when he wrote this, which indicates two things. One: blood loss had weakened him. However, if there is anything we could learn about this man, it will be that he is pretty damn smart - a real genius here, and will figure out something to stop the bleeding before he gets down to composing his messaage. So that only leaves us with the second theory, which is more likely I'd say, is that he was afraid.'

'Pitch Black? The Nightmare? The king of fears?' Bunny snorted.

'Well, I don't think he's an alien. Do you?' retorted Jack. 'As I was saying, yes, he was afraid. Of what I'm not sure, but I can assure you that Pitch _was_ scared. Frightened, even - _desperate_. If he wasn't, he wouldn't have had to use his own blood to leave a message.'

'A message to us?' asked Tooth.

'No, to someone. Someone he knows. Someone he _trusts_.'

'What makes you think so?'

'Because of these numbers,' said Jack. 'These are clearly codes. _Secret_ codes. It can't belong to some organisations. Believe or not, every gang or criminal organisation has eyes and ears everywhere, and things like this could easily reach them, _especially_ when it concerns one of their own. And Pitch seems to be having to deal with some _big_ gang. So no, these codes can't be something widely known. I sense something private here, I tell you.'

'So what are we to do?'

'Three things. Test the DNA. We've been waiting for ten years to catch this guy. I know that it might be no great honour to strike a man when he's most vulnerable, but to hell with honour. The world could do with less a criminal, and this is a master criminal, mind you. Waste no effort to find out who he is and his whereabouts. We'd need _everything_. Second, identify the dead man. We-no, don't ask. I'm tired of explaining. Just do as I say.'

'And the last thing?'

'Find someone to break the code.'

* * *

A/N: Well? What d'you think? I think it's pretty okay. If you agree with me, please review. If you don't, review anyway, but don't praise. Feel free to insult me. I don't mind, really.

One more thing. When I'm say I'm new, I quite mean it. So far I've only wandered the Game of Thrones and A Song of Ice and Fire fandoms (LOL I'm a huge fan of them too) and have only read about five fanfics. Right now I have my eyes on a few Jelsa fanfics but haven't got round to reading 'em yet. If you guys know any good Jelsa fic, recommend them to me! Thanks a lot!

\- Piper L.


	2. Chapter 1

A/N: I've made a little change. Since I know next to nothing about FBI and I want to avoid making mistakes I don't want to, I've decided to change the name of the organisation which Elsa and Jack work for. However, I still haven't come up with a specific name yet so I'll just call it the Organisation, LOL.

Enjoy the ride, folks!

* * *

Chapter 1

'Have you found anything, Sandy?' asked Jack as he strode into the lab and flopped down in one of the chairs. A heavy sigh rolled past his lips. It had been nearly ten hours since the murder occurred. After leaving the crime scene, he and Bunny had returned home and got some more sleep before heading straight to their headquarter. Despite having acquired the much needed rest, he still felt exhausted, every muscle in his body screaming in protest every time he made a move, even the slightest.

'Yes, in fact, I have,' said the man called Sandy, rising from behind his microscope. He actually was born Alexander Sanderson, but most of his friends address him as 'Sandy'. He was a short, stout man around Jack's age, with golden blonde hair and a friendly plump, round face. Sandy was one of Jack's squad, which included himself, Jack, Tooth and Bunny. The four had grown up together and somehow eventually ended up working with each other, though instead of being a field agent like his friends, Sandy took care of the technology and science stuff.

'The victim was Karl Leifsson, 31, a Norwegian, born in Weselton but moved to Arendelle a few years past, and came to Burgess a couple of days ago, said to be on vacation. However, he was in fact a member of Red Crocus, an infamous gang in Arendelle. Thieves and assassins and the such, the lot of them. Most of the high-rated criminals in Arendelle belong to that gang. Every member has a crocus tattooed on their body, which we found on the back of the victim, just a few inches below his left shoulder.'

'And... Pitch Black? What of him?'

'I'm sorry, Jack. I've had my guys test the DNA, even the fingerprints, but so far we've found nothing. I don't think he's even _in_ our database.'

'Well, keep looking. I'm sure we'll find something eventually. What about the code?'

'Our cryptographers could make nothing out of it. But don't worry. I just sent it to someone three minutes ago. If she has received my message by now, then we should be expecting her answer in fifteen minutes at most.'

'Hold on. _She_?'

'Elsa Sorensen. You might have heard of her.'

' _Heard_ of her? Sandy, everyone knows her. A half-Norwegian computer progidy. Graduated San Fransokyo Tech and was recruited by _North himself_ at nineteen. First day at work and she broke into our data system in less than ten minutes. North was pissed, alright, but he couldn't fire her; I think she _challenged_ him. She knows everything about everyone, even things she shouldn't know. The girl's caused more mischiefs in the three years she's worked here than anyone could cause in a lifetime. Nevertheless, I have to admit that she's pretty damn good if she dares to defy North. She's a pretty little thing too, I heard, but no one gets a chance with her.'

'Frostbite, she's called. Quite fitting, I'd dare say. I like her. She's one of a kind. I think you'd enjoy figuring her out,' Sandy said with a smirk. Jack frowned. He hated that smirk. That mysterious smirk that said 'I know something you don't know'. Jack hated not knowing things.

'Wait a minute,' he said. 'Isn't she in the Cyber Division?'

'She is. But she's also a brilliant cryptographer. One of the best I've known, if not the best. She'll decipher the code, Jack, I'm sure of it.'

'Fine. I trust you.'

Sandy nodded. 'Anyway, about the dagger...'

There was a knock on the lab door, followed by North entering. He was wearing the same jovial smile that constantly tugged at his lips. 'Sandy! Jack!' he said in his thick Russian accent. 'How are things going?'

'Not so good,' said Jack. 'But for a Nightmare case? I'd say that it's progressing better than usual.'

'That's good news, isn't it? Well, I'm entrusting this case to you, Jack m'boy.'

'What about Tooth and Bunny?'

'Sorry, Jack. I know you guys always work together, but, well, I'm afraid both of them are otherwise engaged. I'm sending them on another mission; their skills are needed there.'

'No, no, it's okay. I understand. I can manage on my own.'

'What? Who says you're on your own? you alone can't handle this. No, I can't let you face Nightmare alone; it's too dangerous, too risky. You're going to have a partner, Jack.'

North didn't say it out loud, but Jack knew that he was worried about him. Jack had always been the dare-devil, always rushing headlong into the worst of dangers. He was smart, yes, and he was flexible, always managing to find his way out of trouble, but not before getting into trouble first. North was like a father to him, to Bunny, Tooth and Sandy. North was the founder of the Organisation, and he had recruited them as one of the very first members, trained them, loved and cared for them as his own children and trusted them with all his heart.

Jack snorted. 'North, look at me. You _know_ me. I'm Jack Frost the psychopath, Jack Frost the freak. Nobody wants to work with me. They may want to hook up with me, but work? Not in a million years.'

'Wanna bet?'

'Ten bucks.'

'Then prepare to lose your money, Jackie-boy, 'cause someone just volunteered to be your partner!' North laughed.

'Bullshit.'

'Cross my heart. Someone just did.'

'Who, then? Pray tell. I'm curious.'

The smile on North's face suddenly vanished, and his eyes darkened a little, indicating that he liked that person not one bit. 'Ah, you'll find out soon, I promise that. Anyway, I'll leave you to your work, then? Don't forget your report, laddie.'

'Well, at least I don't have to suffer that Easter kangaroo anymore,' said Jack when North had left. 'Please continue. What were you trying to say earlier?'

'Yes, about the dagger. You assumed that it was the dagger Pitch used to kill the man, Leifsson, but we've scanned the body, and the results show that he was killed by a different weapon.'

'A different weapon!'

'Yup. See?' Sandy took the dagger from where it lay on his desk. 'This is a curved blade. My guess is that Leifsson was stabbed with a double-edged spear-point blade, about seven to eight inches. Whatever it was, I can assure you that it was the blade that killed Leifsson, not this dagger.'

Jack cursed himself. He had thought it was a curved blade. He made a mental note to brush up on his knowledge of knives and blades. 'Then why leave this one?'

Sandy shrugged. 'I'm just as clueless as you.'

Jack brought the dagger to his eye level and scrutinised it. 'There's something written on the blade. Latin, maybe?' Jack had learnt Latin at school, but he never paid attention to it, since he never found it necessary to. He had other things to focus on.

'No, I can guarantee that it is not Latin. We haven't identified the language yet. Might be an ancient language, like Old Norse or something. My guys are still looking into the matter.'

'Keep going then. Tell me if there's anything new.'

'I will,' promised Sandy.

Just before Jack was about to take his leave, the door opened, and there stepped in a young woman. She was rather short of stature, with a slender and willowy form. Her hair, which was carefully woven into a braid that fell over her shoulder, was a colour of platinum blonde, so light that he almost mistook it for snow-white. Jack was immediately struck, not by her beauty, for she was indeed a very beautiful woman, but by the elegence and firmness she held in her steps and the confidence and determination which shone brightly in her cerulean eyes.

She caught his gaze, which made him involuntarily blush. Within two sharp glances she'd taken him in and thrust her right hand out (her left hand was holding a file) towards him, speaking in a smooth but monotonous voice: 'Elisabeth Sorensen. A pleasure to make your acquaintance.'

 _So this is the one they keep calling Frostbite._ Jack put on his most charming smile and pressed her hand. 'Beautiful name for a beautiful woman. The pleasure is mine. My name's-'

'Special Agent Jackson Overland Frost, I know who you are,' she said drily, instantly withdrawing her hand. 'I have been granted permission to assist you in the case of Karl Leifsson's murder, but I'm quite sure Mr St North has already informed you about this five minutes ago.'

Jack scrutinized her, letting his eyes wander up and down her face and taking in her whole form, all the while trying to deduce whatever information he could from this very special girl...

He saw nothing.

Jack was shocked, but he tried his best to seem as neutral as possible. 'Well, then you know now that you have the honour of working with the legendary Jack Frost.'

'I see rumours of your modesty do not do you justice, Mr Frost. I look forward to working alongside you. I do hope you won't nip my nose.'

He looked deep into her eyes again. Still nothing.

Jack grinned. 'No promises, Ms Sorensen.' _Why can't I find nothing about this girl?_

She ignored his reply and swiftly turned to Sandy. 'I've got the code you sent me, and managed to decipher them.'

'Thank you, Elsa,' Sandy said, smiling broadly at her. 'You're our saviour.' He glanced at Jack, whose jaw had dropped without him noticing, and gave him an I-told-you-so smile.

'Truly, it's nothing. The code is, in fact, quite simple, but that's why many people can't decipher them. They expect something more... complex.'

'Simplicity is the ultimate sophistication,' quoted Jack.

'And the world is full of obvious things which nobody by any chance ever observes,' said Elsa. 'Da Vinci?'

'Yup. Fan of Sherlock Holmes?'

'Ever since I was a little girl.'

'Nice. Show us what you've got, Sorensen.'

Elsa placed her file on the desk and laid out several papers on which she'd jotted down her notes and calculations. 'As I said, the code is pretty simple. This is the message the killer left us.' She pointed to the sequences of numbers written in blood in the picture.

 _ **1**_ **-2-** _ **12**_ **-** _ **12**_ **8-6-** _ **8**_ **-12-** _ **12**_ **-** _ **4**_ **12-7-11-8**

 _ **12**_ **-** _ **11**_ **-12-** _ **9**_ **-13-** _ **7**_ **-12** _ **6**_ **-9-12** _ **13**_ **-** _ **5**_

 **12-2-6-9** _ **1**_ **-11-** _ **12**_

'Messages are usually written in words, but when they need to be disguised, what's the best and quickest way to do it, especially when you're in a hurry? By using numbers,' said Elsa. 'So each of these numbers must represent a certain letter in the alphabet. But the alphabet contains twenty-six letters - let's just assume that he was using English, and we can all see that no numbers are bigger than thirteen, and none smaller than one. This means we should not consider this theory. However, look at the way the words are slanted. You may have noticed by now that some are slanted to the right and some to the right, yes? Could this have been due to a moment of carelessness? No, impossible. So it must mean something. The question is, what?

'Here's the fun part. The words slanted to the right means from left to right, meaning from the beginning to the end of the alphabet, and the opposite goes to the ones slanted to the left. One, left to right, so we've got A. Two, right to left, we have Y. Just keep going like that and we have:

AYLL SUHOLD OTPS

LKOINGO FRO ME

OYUR APL

Then just unscramble the latters, and the message will be as clear as day.' She pushed the piece of paper on which she'd scribbled the solved puzzle.

Y'ALL SHOULD STOP

LOOKING FOR ME

YOUR PAL,

PITCH BLACK

'This guy has a sense of humour,' said Jack. He could have kicked himself for saying something so lame, but what was he to say? To say he was baffled by Elsa Sorensen's intelligence would be a gross understatement.

Jack looked at the message. The words were strange. 'Y'all should stop looking for me. Your pal, Pitch Black'. What on earth did it mean? To him, it made no sense. Ot was neither a taunt nor a threat. _Think, think, think, THINK!_ he commanded himself. His mind was already spinning like a top, yet he still couldn't think of anything.

'What's your deduction then, Sherlock?' asked Elsa.

'I-I'm afraid I have none. This message means literally nothing to me,' Jack confessed.

'So... that's it? We've lost him?' Sandy frowned.

'No, it can't be. There _must_ be something!'

'Maybe we can still find some link through the Red Crocus,' suggested Sandy.

'Hold on. Is there something I'm missing? What has the Red Crocus to do with this?' asked Elsa with a frown.

'Ah, right. Silly me,' Jack said, slapping his own head and continued to explain to her about the true identity of the dead man and his relations to the gang. Elsa listened patiently, and when Jack had finished, she politely requested to see the body of the victim. Both men were surprised, but they showed her the corpse anyway. The girl only cast so much as one glance at the dead guy then remarked:

'Red Crocus, no doubt. He was one of the messengers.'

'The what?' asked Jack.

'Messengers. Lowest in the ranks of Red Crocus, but still indispensible. They carry messages, information and secrets to aid others in their missions. However, this one wasn't a normal messenger. He was a herald.'

'What's a herald?' inquired Sandy.

'There's a rule in the Red Crocus: once you've joined the gang, there is no turning back; as long as you still live, you can never leave. Those who leave are called deserters. The punishment for a deserter is death. You can run and you can hide all you like, but once you've been marked as a deserter, or a traitor, they will never stop hunting you down. When they've found you, there's no hiding anymore. They won't kill you though, not yet. A herald would be sent to you first, to inform you that your end is coming, and you have two choices: one, sit back and wait, and two, resist, though either of them will eventually lead to your death.'

'You're implying that Pitch Black might be a deserter?' asked Jack.

'Or a turncloak, but turncloak cannot survive that long. There has been no deserter since almost ten years ago.'

'The very same time when Pitch started causing trouble. You seem to know a lot about the Red Crocus.'

'I was born an Arendellian. Everyone in Arendelle knows how the gang operate. I'm quite sure almost a third of the city's population have relations to the gang in one way or another. The easiest, least painful and arduous way to become associated with the gang is to be related to a gang member. Like by marriage.'

'Are you? Related to the gang by marriage, I mean?' Jack asked, smirking.

'I'm not going on a date with you, if that's what you mean. And it's a mission, not a date.'

'I still hold my grounds.' He flashed her a charming smile. Elsa rolled her eyes, but chuckled lightly. She opened her mouth to say something, but instead of words a gasp escaped her lips and her eyes widened, as if something had just dawned on her.

'I know how we can find Pitch Black.'

* * *

A/N: So how do you like Elsa in this chapter? I think she's pretty damn cool. And about the message. I'll admit, it seems quite silly and nonsense. But is it? Well, you'll have to keep on reading to find out.

Until next time (which, hopefully, will be very soon)

\- Piper L.


	3. Chapter 2

A/N: Sorry for letting you guys wait. This chapter was supposed to be posted days ago, but I was having some sort of emotional crisis, so I couldn't get back to writing until yesterday. But that's unimportant now, 'cause I've finally updated, and it's what matters, right?

We'll get to sneak a peek into Elsa's past this time. Just a peek, though. Anyway, enjoy the show!

* * *

Chapter 2

'Are you sure this is going to work? Will this guy help us?' asked Jack worriedly.

'Relax,' said Elsa as she dialed a number on her phone. 'I know he will.'

Jack paced nervously in his office, occasionally glancing at Elsa, who was leaning casually against his desk, phone in her hand and eyes staring intensely at the screen. She had come up with some plan to find Pitch but hadn't told him what it was. Jack didn't like that. It was bad enough she was a mystery to him, and now he couldn't even figure out her actions?

There was nothing wrong with his vision. On their way from the lab to his office, Jack had tried to figure out the people they came across and all succeeded, yet when he turned to Elsa absolutely nothing happened. Impossible. How could it be?

'How come you don't use a smartphone?' he asked, glancing at

'It's too expensive and too inconvenient. Besides, this guy here has been with me for ten years. It's hard to part with it.'

'Ten years?!'

'Most people are too stupid to realise how many wonders they can do with this thing. Plus, it's much more portable, and hard to break.'

'You're unbelievable,' he remarked, which gave Elsa a start. She said nothing, only lowered her head and continued staring at the screen. Deciding that he would only waste his time trying to read her emotions, he returned to his pacing.

Moments later, the person on the other side answered the phone, and Jack stopped dead on his tracks, listening attentively. Elsa had turned on the speaker so that he could listen to the conversation.

'Hello? Elsa, is that you?' the person asked. Male, around sixteen, he decided.

'Hiro, hi! It's been so long,' said Elsa, and her eyes lit up. 'How are you and the others?'

'I'm good, the others are good,' Hiro laughed. 'Holy shit, I can't believe it's you! I mean, when was it? Three years? Four? Where have you been? And how did you get my number, anyway?'

'I have my own ways,' Elsa smirked.

'Right right. Stupid. Should've figured. I've missed you, sis.'

'Missed you too, buddy.' Elsa's smile died, and her face became serious. 'Listen, much as I want to catch up, there's something I need to ask of you.'

'Anything for my almost-sister,' said Hiro merrily. Jack noticed that for a moment something like grief flashed across Elsa's eyes.

'Actually,' she said, 'I need both your and Baymax's help.'

'Just name your wish, Els.'

'Well, I need to find someone. It's a bit urgent. We have his DNA. Can you guys help us?'

'Piece of cake, honey, piece of cake. Send me what you've got.'

'Thank you so much,' Elsa exhaled in relief. 'How can I ever repay you?'

'You don't have t-' Hiro was cut short when another voice suddenly popped in. 'You can always buy me a drink!' Male, somewhere around Elsa's age, a most likely couple of years older, Jack deduced.

Elsa rolled her eyes. 'Nice to see you too, Fred.'

'Remember that you owe me a drink!'

'Of course.'

'Yes! See ya later, Elsa!'

'Sorry about Fred,' said Hiro. 'You know how he is.'

Elsa smiled wistfully. 'Listen... I have to go.'

'Oh, okay. Um, just send me the details. Baymax and I will do the rest.'

'Thanks. Goodbye, Hiro.'

'See ya.'

Elsa hung up, placed the phone on the desk and, throwing her head back, released a sigh.

'Old friends?' asked Jack.

'Yeah,' mumbled Elsa as she was rapidly pressing on the buttons of her phone again, perhaps sending the data to the boy Hiro. 'He's a good lad. A bit of a dork, like his brother, but a lovable dork nonetheless. He's a prodigy in robotics and engineering. Tadashi wouldn't shut up about him.'

'So _his_ name is Tadashi,' chuckled Jack, but his smile died when he saw the morose look in her eyes. 'Shit, I'm sorry, I shouldn't have-'

'It's alright. It's been four years.'

'Accident?'

'That or murder. Either will suit.' Elsa slipped her phone back into the pocket of her jacket.

'You've sent him the data?' asked Jack, trying to change the subject.

Elsa nodded. 'It won't take long. There's nothing more we can do other than wait now.'

'Right. Um, since it's kinda lunchtime, I was wondering,' he paused for a second, expecting her to interrupt him, but seeing that she had not reacted in any way, he proceeded, 'I was wondering whether you'd like to go out and, y'know, grab a bite with me? I know a good place nearby. We can walk, if you'd like, or I can drive you there.'

'Walking would be nice,' said she with a shrug.

'Yeah, it's a pleasant day today. Kinda too pleasant for-wait, what? You mean you agree to have lunch with me?'

'What? It's not a date.'

'People might think otherwise,' Jack grinned toothily at her.

'Let them. I really don't care.'

'Well, then, what are we waiting for? I'm starving!'

* * *

'I'm surprised you didn't take me to McDonald's,' said Elsa as she sat down in her seat, after mumbling her thanks to Jack for pulling out a chair for her. She looked around her, taking in her surroundings. 'This is actually very nice. A cosy little place. How did you come across this pub? Ever taken a girl here?'

'Actually, it was a girl who introduced me to this pub,' said Jack.

'Oh?'

'No, not like that. Well, I _might_ have taken one or two girls here, but the one who showed me this place was actually my sister.'

'That's lovely.'

After they had ordered, Jack leaned forward a bit, put his elbows on the table and laced his fingers. 'So, since we're gonna be partners in this case, shouldn't we, y'know, get to know each other a bit? Partners should know each ther.'

She looked at him for a moment then said: 'You're Jackson Overland Frost. Born on December 21st 1985, aged 31. You have a sister six years your junior named Emily Overland Frost, nicknamed Emma. Your father was Robert Frost - I must say, your family has a sense of humour. He was a rather successful business man who owned several bars and a factory. He divorced your mother when you were twelve and married another woman three years later but had no children by her, so when he died five years ago he left everything for you, his son and heir. You're simply not interested in business, so you renounced your right to your sister, whom you deemed fit for the job. Initially, you wanted to be a policeman, but when you were seventeen, you, Edmund Aster, Thiana Tran and Sandy were recruited by Nicholas St. North, so you became an agent. Your first case, which was ten years ago, was also the first one concerning Nightmare, and ever since you've been specially assigned to deal with him. Therefore, most people consider you to be a professional about Pitch Black, and that you're the best person to handle Nightmare cases.

'You're gifted with the talent to analyse people with great speed and accuracy. The average time for you to analyse a person is 5 seconds, which is, I must say, remarkable - incredible, even. However, you tend to get too cocky, which often results in recklessness and carelessness, and thereby place yourself in considerable danger in many occasions. It's a wonder that you're still living. You have quite a reputation in the organisation. Both good and bad. You're an excellent agent, which makes the boss trusts you. You're a charming man, so many women dote on you. On the other hand, women may like you, but not the men. They don't like constantly being outshone by you. You're also quite eccentric sometimes, which marks you as a terrible partner, except in the case of your squad, whom you've known since childhood. Last but not least, all your passwords are your father's birthday written backwards. And you're absolutely correct.'

'About what?'

'Partners should know each other.'

'Well,' said Jack, shifting uneasily in his seat. 'That's... I think I should change my door lock. Something not electronic would do.'

Elsa laughed. Jack decided that he liked to hear her laugh, and to his surprise he was also laughing. 'That was incredible,' he commented. 'How many men have you scared off in this fashion?'

'Make a guess.'

'I don't know, five?'

'It's uncountable.'

'Oh dear. Well, it seems you know quite a lot about me already. Why don't you tell me a bit about you?'

'I was hoping that I could personally witness the famous Jack Frost's talent. Come on, read me. What can you see? I told you what I know about you; it's only fair that you do the same.'

Jack scrutinised her. Still nothing. Secrets, mystery, enigma, veiled. hidden, _concealed_. Those were the only words he could use to describe what he found in her. She was still a complete mystery to him.

He shook his head, smiling gently. 'It's rude to pry into a woman's private life. I'd prefer to earn your trust. You can tell me about yourself now or when you're ready.'

'What a shame.' Elsa looked downcast, but also... relieved? 'There's not much to be said, actually. I'm sure you can know all about me if you ask Sandy.'

'A computer prodigy in San Fransokyo Tech. Right. And I'm some nameless cop,' said Jack sarcastically, which made Elsa blush profusely.

Just that moment, the waitress arrived with their meal, flirted with Jack a bit then left him and an amused Elsa to their own business. The two of them continued to talk. Somehow, the conversation later turned to the subject of family, and when Jack asked about Elsa's family, much to his astonishment, she almost panicked. Her back was rigid, her eyes darting around nervously, desperate to avoid his gaze, and she started fidgetting with her hands.

'I'd prefer not to talk about it,' she mumbled almost inaudibly.

'It's okay. I'm sorry for making you uncomfortable,' he apologised. Elsa only nodded and quietly ate her food. The rest of their meal was eaten in silence. When both of them had finished, Jack paid the bills, despite Elsa's protests, and the duo walked back to the organisation's building.

'So, is this your first time working in the field?' asked Jack.

'Yes.'

'Nervous?'

'Excited.'

'That's cool. First time in the field, I was terrified.'

'I thought you handled your first case well enough. Thanks to your success in solving that one, you're now a legend. The Sherlock Holmes of Burgess.'

'You don't approve?'

'On the contrary, I think it's rather fitting. I admire your talents; there's no doubt about it.'

'Then what's the problem?'

'You don't have a Watson.'

'Well, I have you.'

Elsa laughed. 'Frost, I-'.

She didn't get to finish her sentence, for her phone suddenly buzzed. She dug her hand into her pocket and fumbled for the phone. Pressing 'answer', she raised it to her ear. Jack listened to her, heart pounding in his ears, and it almost leapt out of his sternum when Elsa ended the call and turned to him, the answer on her lips.

'He's found him.'


End file.
